Ichthus

Ich″thus (ĭk″thŭs), n. [Gr. ιχθὔσ.] In early Christian and ecclesiastical art, an emblematic fish, or the Greek word for fish, which combined the initials of the Greek words Ιησου̑σ, Cηριστόσ, Θεου̑ ΓιόσΣωτήρ, Jesus, Christ, Son of God, Savior.